Technical Abstract:
Carrots (Daucus carota L.) were domesticated over 1,000 years ago in Central Asia. Two traits selected during domestication were increased carotenoid accumulation (white -> yellow -> orange root color) and decreased lateral root formation. While some preliminary research has been conducted on the underlying genetic control of these traits, no genetic loci have been identified. To better understand these traits, a recombinant inbred line (RIL) population was developed from a cross between a white-branched wild carrot (Queen Anne’s lace - QAL) and a smooth-orange inbred line (B493). The population was phenotyped for carotenoid accumulation using visual assessment and High Performance Liquid Chromatography (HPLC) and found to segregate 3:1, indicating that a single locus, y, controls the trait. Additionally, a novel scale and procedure was developed for scoring lateral root prominence. 172 F4 RILs and population parents are being genotyped using a genotyping-by-sequencing platform at the University of Wisconsin - Madison Biotechnology Center to identify genome-wide variation and quantitative trait loci for carotenoid accumulation and lateral root prominence. Further, as more of the carrot genome becomes available we will begin a candidate gene search for these traits. Molecular markers that are developed will facilitate rapid genotypic screening for carrot population improvement.